I recently read a theory about the movie Laura that I find interesting. I don't think I'm spoiling anything because most of the resumes on this movie reveal the one key moment of the story but if you didn't watch it you might better not read the rest of my post.

According to this interpretation the movie is less about Laura than about the detective investigating her disappearance. The character played by Dana Andrews discovered her portray which made quite an impression on him. He later falls asleep at her place and Laura, alive, enters the room. He awakes at this moment and she stands in front of him like a vision.
To some viewers this strange scene suggests the reappearance of Laura and the rest of the story is not the reality but a dream of the detective, asleep under her portray. Laura is dead but the beauty and enigma of her portray is enough to make him fall in love and inspire him a dream or a fantasy about her.
I like this interpretation of the story. If it's what the director had in mind when he made the movie the choice of Gene for the role is even more interesting because she was not only chosen to play a woman but also to incarnate an ideal.